In most ophthalmic procedures, a first step is to gain secure access to the surgical field in a way that is not painful to the patient. For decades this has been done with a variety of eyelid retractors commonly referred to as speculums. Speculums are usually constructed from stainless steel and have “blades” at the end of two arms, which slip underneath the eyelids. These blades are then mechanically or spring activated to open the eyelids during surgery. Since the anatomy and orbital construct of each patient is different a variety of speculums exist.
The most common speculums on the market are produced entirely from wire and are simple and inexpensive. One problem with wire speculums is that the wire weakens over time lessening the strength to keep the lids properly retracted.
Most patients are awake during cataract surgery leading to a second problem with wire speculums in that the patient has the ability to squint thereby limiting the surgical field.
Another problem is that the blades open from a single pivot point causing the lids to be retracted in a “V” shape. The part of the blade furthest from the pivot point opens wider than the end closest to the pivot point. The result is that the inferior and superior aspects of the blades are spaced apart with different distances.
A variety of mechanical speculums are on the market that attempt to both open the lids to the extent desired and to control a “squinter”. Most of these speculums utilize a screw mechanism and a single pivot point to retract the lids. These speculums suffer from the same “V” shape opening problem as the wire speculums.
Cataract surgery performed with a femtosecond laser is one of the newest technologies available to eye surgeons. The unprecedented accuracy that the femtosecond laser affords a surgeon can produce better surgical outcomes and improved healing and vision for the patient.
One of the challenges to femtosecond laser technology is to provide for “docking” the laser to the patient eye. This is done through an interface device on the bottom of the laser that aspirates onto the patient's eye.
Docking is not always the easiest task since many patients have astigmatism, i.e., an irregularly shaped cornea. In addition, prior art speculums can also cause a misshapen cornea due to cornea pressure from the blades of the speculum. Cornea pressure from the blades of the speculum is a two-fold problem. First the single pivot point of prior art speculum blades causes the inferior portion of the blades to be further apart than the superior portion of the blades. Second the blades themselves are straight and press into the globe creating pressure and distortion.